ATOMIC_ADD(3clc)

💖 NAME 💖

okay bestie, gather round, this is atomic_add — the atomic_add functions. that's it, that's the name, iconic behavior honestly ✨

this page lives in the OpenCL Manual (3clc), so like… yeah, we're in OpenCL land now 🦋

here's the whole squad, exactly as they show up:

int atomic_add(volatile global(3clc) int *p, int val);

unsigned int atomic_add(volatile global(3clc) unsigned int *p,
                        unsigned int val);

int atomic_add(volatile local(3clc) int *p, int val);

unsigned int atomic_add(volatile local(3clc) unsigned int *p,
                        unsigned int val);

four flavors, no cap 🫶

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🌸 DESCRIPTION 🌸

okay so here's the tea, and it's actually so simple it's giving main character energy:

• read the 32-bit value (we call it old) that's stored at the location p is pointing at 👀
• compute (old + val) 🧮
• store that result right back at the location p points to 💾
• and the function returns old — like, the value from before you added anything, she remembers the past fr fr 💅

and then, plot twist 🌈 — there's a 64-bit version of this function, and it's called atom_add(3clc). it does NOT come free, bestie. it's only enabled by cl_khr_int64_base_atomics(3clc). no extension, no 64-bit, periodt 🔥

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🎀 SPECIFICATION 🎀

OpenCL Specification[1] 👑

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✨ SEE ALSO ✨

• atomicFunctions(3clc)
• atom_add(3clc)

go read those too, they're the friend group 🦋

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👑 AUTHORS 👑

The Khronos Group 💜

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📜 COPYRIGHT 📜

Copyright © 2007-2011 The Khronos Group Inc.

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and/or associated documentation files (the "Materials"), to deal in the Materials without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Materials, and to permit persons to whom the Materials are furnished to do so, subject to the following conditions:

the above copyright notice and this permission notice shall be included in all copies or substantial portions of the Materials.

like fr fr, keep the notice in there. it's not optional and it's not a vibe suggestion 💀

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💀 NOTES 💀

1. OpenCL Specification page 279, section 6.12.11 - Atomic Functions for 32-bit integers

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The Khronos Group dropped this on 01/14/2021, and the whole thing answers to the name ATOMIC_ADD(3clc) — anyway that's the page, you ate it, go forth and atomically add bestie 🫶💖✨